In recent years, organic EL (Electro Luminescence) display apparatuses have started to be in practical use. An organic EL display apparatus includes, for each pixel, at least one organic EL element (Organic Light Emitting Diode: OLED) and at least one TFT (Thin Film Transistor) for controlling the current flow supplied to the OLED. Each pixel is defined by a lattice-shaped structure formed from an insulating material (called “banks” or “partition walls”). Banks are provided on a flattening film that is formed so as to cover a circuit including TFTs (called a “driving circuit” or “backplane circuit”) (see, for example, Patent Document No. 1).
An organic EL element of each pixel includes an anode that is connected to a driving circuit, an organic EL layer provided on the anode, and a cathode provided on the organic EL layer. An organic EL layer has a layered structure including a plurality of layers formed from an organic semiconductor material. For example, the layered structure includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer, in this order starting from the anode side. Organic EL layers of a red pixel, a green pixel and a blue pixel include a light emitting layer that emits red light, a light emitting layer that emits green light and a light emitting layer that emits blue light, respectively.
The organic EL layer is formed on an anode located in a region surrounded by banks (a region to be a pixel) by using a vacuum deposition method or a print method. That is, methods for forming an organic EL layer are generally classified into “deposition-based methods” and “print-based methods”.